The factor of safety principle is about a system’s degree of flexibility during regarding the preparation for structural uncertainty in error conditions. The bigger this value, the greater risk-control is possible for the designed system’s emergency situations.
This principle should be considered in all context requiring error handling. In particular, it is often used in structural design, because structures are designed to endure heavier loads than those they are expected to hold.
#1 Original sources: Universal Principles of Design
The O-ring design of the rocket booster of the space shuttle Challenger was designed to have a “3” value of safety factor. It was found out that at low temperatures the O-rings were eroded, making the safety factor go below three. On the day of the launch, engineers objected to launching the rocket because the temperature of the launch pad was very low. The launch was proceeded as planned, believing that the safety factor would guarantee its success. Unfortunately, the launch failed, as the safety factor decreased due to the temperature condition.
#2 Online sources: (1) Link to Visual wall, (2) Crosswalk lighting
(1) A visual wall; a laser hologram traffic light concept by artist Hanyoung.
< Image source : Google >
(2) Crosswalk lighting in South Korea; reduces the danger of pedestrians by alerting drivers through the strong light rays projected when pedestrians cross.
#3 Real life: Playground slide
Children’s slide needs to bear a higher load than normally expected, since it needs to account for uses by larger children as well as misuse.